U.S. patent application number 09/775683 was filed with the patent office on 2002-08-08 for variable focus indirect lighting fixture.
Invention is credited to Loughrey, James F..
Application Number | 20020105807 09/775683 |
Document ID | / |
Family ID | 25105171 |
Filed Date | 2002-08-08 |
United States Patent
Application |
20020105807 |
Kind Code |
A1 |
Loughrey, James F. |
August 8, 2002 |
Variable focus indirect lighting fixture
Abstract
A variable focus indirect lighting fixture has a pair of first
reflectors with each reflector arranged to substantially surround a
light source, and a second variable focus reflector positioned in
front of the first reflectors. Each of the first reflectors has an
opening arranged to provide direct rumination from the light
source. The second reflector is positioned in front of each opening
of the pair of first reflectors to receive and reflect the
lumination from each light source passing through each opening. The
second reflector has a pair of inner, concave surfaces arranged
such that each inner surface faces a respective opening of the
first reflectors and is arranged to receive and reflect the
lumination from the respective light source passing through the
opening of each of the first reflectors. The inner surfaces are
aligned along a center line of the second reflector between the
pair of first reflectors. The center line is adjustable to modify
the concavity of the inner surfaces of the second reflector.
Adjustment of the center line varies the focus of the light output
reflected from the second reflector of the fixture.
Inventors: |
Loughrey, James F.; (Stacy,
MN) |
Correspondence
Address: |
LOWE HAUPTMAN GILMAN & BERNER, LLP
Suite 310
1700 Diagonal Road
Alexandria
VA
22314
US
|
Family ID: |
25105171 |
Appl. No.: |
09/775683 |
Filed: |
February 5, 2001 |
Current U.S.
Class: |
362/278 ;
362/282; 362/298; 362/320; 362/322; 362/346 |
Current CPC
Class: |
F21V 7/005 20130101;
F21Y 2103/00 20130101; F21S 8/02 20130101; F21V 14/04 20130101;
F21Y 2113/00 20130101; F21V 7/16 20130101; F21V 7/0008
20130101 |
Class at
Publication: |
362/278 ;
362/282; 362/320; 362/322; 362/346; 362/298 |
International
Class: |
F21V 001/00 |
Claims
What I claim is:
1. A method of providing variable focussed indirect light from a
lighting fixture, wherein the fixture has at least one light
source, a first reflector substantially surrounding the light
source and having an opening, comprising the steps of: directing
lumination from the light source through the opening; reflecting
the rumination from the light source passing through the opening of
the first reflector with a second variable focus reflector
positioned in front of the opening; and raising or lowering a
center point of the second variable focus reflector directing light
to thereby adjust the focus of rumination transmitted by the
fixture to an area to be illuminated.
2. The method as claimed in claim 1, wherein said raising or
lowering step is performed manually.
3. The method as claimed in claim 1, wherein said raising or
lowering step is performed automatically.
4. The method as claimed in claim 3, wherein said raising or
lowering step is performed in response to commands received from a
control remotely located from the lighting fixture.
5. A variable focus indirect lighting fixture comprising: a first
reflector mounted to substantially surrounding a light source,
wherein said first reflector has an opening arranged to direct
lumination from the light source; a second variable focus reflector
positioned in front of the opening of said first reflector and
arranged to receive and reflect the rumination from the light
source passing through the opening of said first reflector, wherein
said second reflector has an inner, reflective, curved surface
facing the opening of said first reflector and said second
reflector has an adjustable center point arranged to modify the
curvature of said second reflector.
6. The fixture as claimed in claim 5, wherein said adjustable
center point is manually adjustable.
7. The fixture as claimed in claim 5, wherein said adjustable
center point is automatically adjustable.
8. The fixture as claimed in claim 7, wherein said adjustable
center point is configured to receive commands from a control
remotely located from said lighting fixture and automatically raise
or lower the center point of said lighting fixture.
9. The fixture as claimed in claim 5, wherein the light source
comprises at least one of a compact fluorescent bulb, a self
ballasted fluorescent bulb, an incandescent bulb, an arc tube, a
metal halide bulb, a mercury bulb, a low pressure sodium bulb, a
high pressure sodium bulb, a light emitting diode, and a variable
output single constant source light source.
10. The fixture as claimed in claim 5, wherein said second variable
focus reflector has at least one reflective surface.
11. The fixture as claimed in claim 5, wherein said second variable
focus reflector has at least one concave surface.
12. The fixture as claimed in claim 5, wherein said inner,
reflective, curved surface of said second variable focus reflector
is at least one of a parabola, ellipse, and an annular surface.
13. A variable focus indirect lighting fixture comprising: a pair
of first reflectors wherein each reflector is arranged to
substantially surround a light source, wherein each of said first
reflectors has an opening arranged to direct lumination from the
light source; and a second variable focus reflector positioned in
front of each opening of said first reflectors and arranged to
receive and reflect the rumination from each light source passing
through each opening of said first reflectors, wherein said second
reflector has a pair of inner, curved surfaces arranged such that
each inner surface faces a respective opening of said first
reflectors to receive and reflect the lumination from the
respective light source passing through the opening of each of said
first reflectors, wherein said inner surfaces are aligned along a
center line of said second reflector between said pair of first
reflectors, and wherein the center line is adjustable to modify the
curvature of the inner surfaces of said second reflector.
14. The fixture as claimed in claim 13, wherein said adjustable
center point is manually adjustable.
15. The fixture as claimed in claim 13, wherein said adjustable
center point is automatically adjustable.
16. The fixture as claimed in claim 15, wherein said adjustable
center point is configured to receive commands from a control
remotely located from said lighting fixture and automatically raise
or lower the center point of said lighting fixture.
17. The fixture as claimed in claim 13, wherein the light source
comprises at least one of a compact fluorescent bulb, a self
ballasted fluorescent bulb, an incandescent bulb, an arc tube, a
metal halide bulb, a mercury bulb, a low pressure sodium bulb, a
high pressure sodium bulb, a light emitting diode, and a variable
output single constant source light source.
18. The fixture as claimed in claim 13, wherein said second
variable focus reflector has at least one reflective surface.
19. The fixture as claimed in claim 13, wherein said second
variable focus reflector has at least one concave surface.
20. The fixture as claimed in claim 13, wherein said inner,
reflective, curved surface of said second variable focus reflector
is at least one of a parabola, ellipse, and an annular surface.
21. A variable focus indirect lighting fixture comprising: at least
two first reflectors wherein each reflector is arranged to
substantially surround a light source, wherein each of said first
reflectors has an opening arranged to direct lumination from the
light source; and a second variable focus reflector positioned in
front of each opening of said first reflectors and arranged to
receive and reflect the rumination from each light source passing
through each opening of said first reflectors, wherein said second
reflector has inner, curved surfaces arranged such that each inner
surface faces a respective opening of said first reflectors and
arranged to receive and reflect the lumination from the respective
light source passing through the opening of each of said first
reflectors, wherein said inner surfaces are arranged about a center
point of said second reflector between said at least two first
reflectors, and wherein the center point is adjustable to modify
the curvature of the inner surfaces of said second reflector.
22. A variable focus indirect lighting fixture, comprising: a light
source; a reflector positioned above the light source and including
a reflective surface arranged to reflect light from the source as
indirect light into a space; and an adjustment member operatively
attached to the reflector surface to move the surface relative to
the light thereby changing an illumination angle.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to lighting fixtures
and, more particularly, to lighting fixtures providing indirect
light or luminance. Still more particularly, the present invention
relates to variable focus indirect lighting fixtures.
BACKGROUND ART
[0002] Indirect lighting is widely recognized as the best type of
lighting as it provides even illumination without the glare of
direct illumination from the light source. Indirect lighting which
resembles lumination from a skylight is the most desirable type of
lighting. The benefit of indirect lighting is that the source of
light, i.e., the point of rumination, is never visible. It is
similar to the illumination received on a cloudy day where the sun
is not visible. The lack of glare is one of the prime benefits of
indirect lighting. The even distribution of the lighting is also a
major benefit.
[0003] Indirect lighting through skylights can be focused on a
specific area by the size of the skylight and the distance between
the roof and the ceiling where the skylight is located. The ability
to control indirect lighting to cover the space to be illuminated
or the task area to be illuminated is not available through the use
of commercially available lighting fixtures. Thus, there is a need
in the art for an indirect lighting fixture control.
[0004] A prior approach to solving the problem of providing
indirect lighting for indoor recessed lighting environments is a
recessed, indirect lighting fixture, e.g., the Atrium fixture
available from Eclairage Axis Lighting Inc. FIG. 1 is a perspective
view of the recessed, indirect lighting fixture of the prior
art.
[0005] A recessed, indirect lighting fixture 10 is mounted in a
typical office environment ceiling 12. The ceiling 12 includes
support beams 14 supporting ceiling panels 16 in a typical grid
arrangement. These support beams 14 are normally suspended from an
office space ceiling (not shown) via support wires (not shown). The
lighting fixture 10 rests on, or is attached to, support beams 14
and fully covers an opening 15 in ceiling 12 of the same size as
ceiling panel 16. Typical ceiling panel 16 dimensions are either
two foot square or two feet by four feet.
[0006] The lighting fixture 10 includes a light source 18 mounted
above ceiling 12 on opposite interior sides of the fixture 10 and
substantially vertically aligned over the support beam 14. The
light source 18, e.g., a fluorescent light tube, is partially
surrounded by a channel 20, e.g., an aluminum extruded channel,
extending coextensive with the opening 15 in the ceiling 12 for the
fixture 10. The channel 20 is generally U-shaped and directs light
from light source 18 toward a concave surface 21 formed by a curved
reflector 22 forming a portion of the top surface of fixture
10.
[0007] Two curved reflectors 22 are joined together at common edges
along a centerline of fixture 10 to form an upper side of the
fixture. A single piece of material having two curved portions may
be used in place of two separate pieces being joined. The
transversely extending ends of the fixture 10 not having light
source 18 have a substantially vertical end wall 24 connected to
each of the curved reflectors 24 along a top edge and rest on, or
are attached to, a transverse beam support 14a along a lower edge
thereof.
[0008] Using the above-described lighting fixture 10, light is
transmitted from light source 18 toward the concave surface 21 of
curved reflector 22. The light reflects off concave surface 21 and
passes through opening 15 to illuminate the office space below
ceiling 12. As depicted in the side view of fixture 10 in FIG. 2,
the angle of light distribution 26 using the recessed, indirect
lighting fixture described above is approximately one hundred fifty
(150) degrees. Thus, the fixture 10 provides a uniform light
distribution over a large angle. However, there are many situations
where a uniform distribution of light is needed only in a specific
location, e.g., conference rooms, television studios, football or
basketball arenas. In these situations, it is desirable to have
more light on a specific subject or location. e.g., players on the
basketball court or documents being read at a conference table, and
fixture 10 is not able to focus the light as required. Therefore,
there is a need in the art for a focussed indirect lighting
fixture.
[0009] Further, certain applications of indirect lighting require
different focus settings at different times. For instance, if a
person is making a presentation in a conference room the lighting
should be focussed on the presenter and the presentation, i.e., a
narrow focus; however, if a discussion is occurring at the
conference table, the lighting should be focussed on the table and
any documents at the table, i.e., a broader focus. A typical
solution for multiple levels of lighting focus is to use multiple
differing light fixtures, e.g., recessed fluorescent lighting for a
broader focus and incandescent directional lighting for narrow
focus. Thus, there is a need in the art for a variable focus
indirect lighting fixture.
[0010] The current practice in lighting is to use uplighting on
suspended fixtures using the ceiling as the reflector. This
practice is extremely inefficient and impractical and creates hot
spots on the ceiling without controlling where the light is to be
directed.
[0011] Current practice and currently available products on the
market are all fixture designs with the lamps and reflectors being
set with no adjustability or variation available either from the
factory or in the field at the fixture. A field adjustable lighting
fixture is particularly suited to television studios or video
conferencing rooms. In television studios, the trend is toward the
use of fluorescent lighting because such lighting provides a more
uniform lumination lacking hot spots at a more comfortable cooler
temperature, i.e., the person or persons under the light are not
subjected to heat from the lights. The use of variable focus direct
lighting fixtures has long been used in theater and television
studios to control the beam spread of the luminaires.
[0012] Television studios have long used skrims or diffusers over
either incandescent or fluorescent fixtures to soften the effect of
the light source. Unfortunately, this has resulted in fires from
the very hot incandescent lamps and a loss of light intensity when
used with fluorescent lamps. A variable focus indirect lighting
fixture would allow open aperture fixtures to efficiently disperse
light over a controllable area with no glare and no direct light.
Therefore, there is a need in the art for a variable focus indirect
lighting fixture for use in television studios, video conference
rooms, and theaters.
SUMMARY OF THE INVENTION
[0013] It is an object of the present invention to provide a
variable focus indirect lighting fixture.
[0014] Another object of the present invention is to provide a
variable focus indirect lighting fixture for use in television
studios, video conference rooms, and theaters.
[0015] The above-described objects are achieved by a variable focus
indirect lighting fixture. The lighting fixture has a pair of first
reflectors with each reflector arranged to substantially surround a
light source, and a second variable focus reflector positioned in
front of the first reflectors. Each of the first reflectors has an
opening arranged to direct rumination from the light source. The
second reflector is positioned in front of each opening of the pair
of first reflectors and arranged to receive and reflect the
rumination from each light source passing through each opening of
the pair of first reflectors. The second reflector has a pair of
inner, concave surfaces arranged such that each inner surface faces
a respective opening of the first reflectors and is arranged to
receive and reflect the rumination from the respective light source
passing through the opening of each of the first reflectors. The
inner surfaces are aligned along a center line of the second
reflector between the pair of first reflectors. The center line is
adjustable to modify the concavity of the inner surfaces of the
second reflector. Adjustment of the center line varies the focus of
the light output reflected from the second reflector of the
fixture.
[0016] In a method aspect, variable focussed indirect light is
provided from a lighting fixture having at least one light source,
a first reflector substantially surrounding the light source, and a
second variable focus reflector positioned in front of the first
reflector. The first reflector has an opening for directing the
lumination from the light source and the second reflector is
positioned in front of the opening of the first reflector to
receive and reflect the rumination from the light source passing
through the opening of the first reflector. The second reflector
has an adjustable center point for raising and lowering the center
point of the second reflector thereby adjusting the focus of
rumination transmitted by the fixture. The center point of the
second reflector is raised or lowered to adjust the focus of light
transmitted from the fixture to an area to be illuminated.
[0017] Further, a lighting fixture apparatus is described as having
a first reflector for substantially surrounding a light source, and
a second variable focus reflector positioned in front of the first
reflector. The first reflector has an opening arranged to direct
rumination from the light source and the second reflector is
arranged to receive and reflect the rumination from the light
source passing through the opening of the first reflector. The
second reflector has an inner, reflective, curved surface facing
the opening of the first reflector and the second reflector has an
adjustable center point arranged to modify the curvature of the
second reflector to adjust the focus of light transmitted from the
fixture to an area to be illuminated.
[0018] In an additional embodiment, the apparatus described above
includes a pair of first reflectors surrounding a pair of light
sources and the second reflector includes a pair of inner,
reflective, curved surfaces for receiving and reflecting the
rumination from the light source.
[0019] In a still further embodiment, the apparatus described above
includes multiple first reflectors surrounding multiple light
sources and the second reflector includes multiple inner,
reflective, curved surfaces corresponding to the multiple first
reflectors for receiving and reflecting the rumination from the
light sources.
[0020] Still other objects and advantages of the present invention
will become readily apparent to those skilled in the art from the
following detailed description, wherein the preferred embodiments
of the invention are shown and described, simply by way of
illustration of the best mode contemplated of carrying out the
invention. As will be realized, the invention is capable of other
and different embodiments, and its several details are capable of
modifications in various obvious respects, all without departing
from the invention. Accordingly, the drawings and description
thereof are to be regarded as illustrative in nature, and not as
restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The present invention is illustrated by way of example, and
not by limitation, in the figures of the accompanying drawings,
wherein elements having the same reference numeral designations
represent like elements throughout and wherein:
[0022] FIG. 1 is a perspective view of a prior art indirect
lighting fixture;
[0023] FIG. 2 is a side view of the fixture of FIG. 1;
[0024] FIG. 3 is a side view of an embodiment of the present
invention;
[0025] FIG. 4 is a side view of the light distribution angle of the
present invention in one configuration;
[0026] FIG. 5 is a side view of the light distribution angle of the
present invention in another configuration;
[0027] FIG. 6 is a top view of the embodiment of FIG. 3 of the
present invention;
[0028] FIG. 7 is a top view of another embodiment of the present
invention;
[0029] FIG. 8 is a side view of another embodiment of the present
invention having a single light source;
[0030] FIG. 9 is a side view of another embodiment of the present
invention having a telescoping centerpiece;
[0031] FIG. 10 is a side view of another embodiment of the present
invention having an offset adjustment device;
[0032] FIG. 11 is a side view of another embodiment of the present
invention having individual left and right adjustment devices;
[0033] FIG. 12 is a side view of the embodiment of FIG. 7;
[0034] FIG. 13 is a perspective view of the embodiment of FIG. 7;
and
[0035] FIG. 14 is a perspective view of a conference room using the
present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0036] The Variable Focus Indirect Lighting Fixture (VFILF),
generally indicated by reference numeral 30 in FIG. 3, of the
present invention controls the focus of indirect lighting from a
lighting fixture 30 by using reflectors 32 having a variable shape.
The beam angle of a lighting fixture is defined as the angle where
50% of the light output of the fixture is concentrated. The field
angle of a lighting fixture is defined as the angle where 90% of
the light output of the fixture is concentrated. The center of the
reflector 32 is adjustable either at the fixture or at the time of
manufacture so that the beam angle and the field angle is
controllable to direct the luminance output of the fixture 30.
[0037] The overhead profile of the lighting fixture 30 may be of
any shape necessary for a given application, i.e., square,
rectangular, circular, or triangular. The VFILF 30 is now described
in detail with reference to FIG. 3.
[0038] The design of the field adjustable VFILF can be very
sophisticated or simple depending upon customer requirements and
budget. The VFILF is similar in design to the recessed, indirect
lighting fixture 10 of the prior art (FIG. 1 and 2); however, the
improved VFILF includes a variable focus adjustability not found on
the prior art indirect lighting fixture.
[0039] The VFILF 30 is shown positioned within ceiling 12 over
ceiling opening 15 and supported by support beams 14. The VFILF 30
includes an upper adjustable reflector 32 positioned above and able
to slide over a lower semi-circular reflector 34. A U-shaped frame
36 is positioned over upper reflector 32 for supporting an
adjustment device 38 for raising and lowering the center 33 of
upper reflector 32. The lower reflector 34 partially surrounds a
tight source 40 and directs and reflects the light output of light
source 40 toward upper reflector 32. The lower reflector 34 is of a
fixed shape and forms a semicircular reflector, e.g., an elliptical
forward throw reflector as known in the art. In alternate
embodiments, the lower reflector 34 may be of a type known as
segmented, double slotted, or any type or shape able to reflect the
light source 40 output toward upper reflector 32.
[0040] The upper reflector 32 is held on top of the lower reflector
34 and slides in and out, i.e., vertically up and down along
directional arrow 41 with respect to the side view of FIG. 3 and in
and out of the page with respect to the top view of FIG. 6, as
required to form the proper arc, e.g., parabolic, of the upper
reflector 32 focussing or dispersing the light thrown forward by
the lower reflector. That is, the upper reflector 32 reflects light
received from light source 40 and lower reflector 34 toward opening
15 in ceiling 12. The distal ends of upper reflector 32 slide past
lower reflector 34. With respect to FIG. 3, the distal end 35 of
upper reflector 32 protrudes beyond lower reflector 34 when the
upper reflector's center point 33 is at its maximum height, i.e.,
dashed line 46. In this case, the upper reflector 32 slides over
and beyond lower reflector 34 as the center point 33 is raised. The
upper reflector 32 may be any type of reflective material, e.g.,
white plastic, aluminum, mylar cloth fabric, or fiberglass, to
reflect light from light source 40.
[0041] In one alternate embodiment, upper reflector 32 is a
stretchable material, e.g., stretchable mylar or another
stretchable reflective material, and the distal ends 35 are
attached to the upper edge of lower reflector 34. As center point
33 is raised and lowered, the upper reflector 32 stretches to
accommodate the change in dimension. Stiffening or support stays
(not shown) may be needed in connection with upper reflector 32 in
order to produce the curve of upper reflector 32.
[0042] In another alternate embodiment depicted in FIG. 9, upper
reflector 32 includes a telescoping centerpiece 50 and curved
sidepiece reflectors 52 affixed and supported at distal end 35 by
the upper edge of lower reflector 34 and supported at the proximal
end 53 by telescoping centerpiece 50. As telescoping centerpiece 50
is raised or lowered the curved sidepiece reflectors proximal end
53 slide over the upper portion of the telescoping centerpiece 50
and curved sidepiece reflectors 52 rotate about distal end 35. It
is to be understood that more than one telescoping segment may be
required in certain embodiments to obtain the necessary curvature
and/or length of upper reflector 32.
[0043] In most situations, the intended application or installation
location dictates the method used to adjust the upper reflector 32,
e.g., manual or automatic. The upper reflector 32 is adjusted by
raising or lowering the center point 33 of the upper reflector in
order to modify the angle at which light is reflected and
transmitted from lighting fixture 30. The upper reflector 32 may be
deformed in shape over a range of angles from obtuse or nearly flat
at the highest position (shown as a dotted line 46) to acute at the
lowest position (shown as a dot-dash line 48).
[0044] Raising or lowering the center point 33 of the upper
reflector 32 can be accomplished by a simple screw similar to those
used to open or close a roof vent in a trailer, or by a remote or
computer controlled electric motor or an air operated solenoid. As
shown in FIG. 3, a wing-nut 42 is threaded on a threaded bolt 44 to
raise and lower the center of reflector 32. As wing-nut 42 is
threaded onto the bolt 44, the center point 33 is raised toward the
U-shaped frame 36 deforming upper reflector 32 toward a more flat
position. In effect, the inverted peak formed at the center point
33 of upper reflector 32 is greatest at the lowest position 48 and
lowest, or in some cases non-existent at the highest position
46.
[0045] It is to be understood that U-shaped frame 36 is not
necessary in all installations and may be replaced by another
mechanism to provide support for adjustment device 38, e.g.,
adjustment device may be attached directly to an overhead support
or the ceiling above the drop ceiling 12. Further, it is to be
understood that although the present invention is described with
respect to a center point 33 located at the center of second
reflector 32, the center point need not be located at the center of
second reflector 32. In fact, in different installation locations
it may be beneficial to have an offset center point 33 in order to
provide differing amounts of illumination to different areas. For
example as depicted in FIG. 10, the center point 33 and adjustment
device 38 may be located more closely to the left-hand light source
40 providing a longer curve to the right-hand inner, reflective
surface 32A of second reflector 32 as compared to the left-hand
surface 32B.
[0046] Further still, as depicted in FIG. 11, separate adjustment
devices, e.g., left-hand adjustment device 38A and right-hand
adjustment device 38B, may be employed to separately adjust the
curvature of the left and right-hand portions of the inner,
reflective surfaces 32A and 32B of second reflector 32.
[0047] FIGS. 4 and 5 are side views of fixture 30 of FIG. 3 with
variable focus reflector 32 in two different focus positions. In
FIG. 4. the focus of reflector 32 is set with the adjustment device
38 set to a length B resulting in a distribution or field angle A
of the light from the pair of light sources 40 reflecting off the
reflector 32. In FIG. 5, the adjustment device 38 is set to a
length D which is longer than length B in FIG. 4, thus deepening
penetration of center point 33 into fixture 30. As a result, light
from the pair of light sources 40 is reflected at a greater angle
from variable focus reflector 32 and forms a distribution or field
angle C smaller than angle A in FIG. 4. By adjusting the adjustment
device 38 described in detail above, a user can quickly and easily
vary the amount of illumination provided to an area from a wide
angle distribution, e.g., distribution angle A, or approximately
170 degrees, as in FIG. 4, to a more narrow distribution, e.g.,
distribution angle C, or approximately 50 degrees, as in FIG.
5.
[0048] FIG. 6 is a top view of the VFILF 30 of FIG. 3. As can be
seen in FIG. 6, the center point 33 forms a center line of fixture
30 and the light sources 40 are installed along either side of the
center line.
[0049] FIG. 7 is a top view of another embodiment of the VFILF in
which four light sources 40 are positioned along corresponding
sides of fixture 30 and upper reflector 34 has quadrant forming
intersecting center lines 35 intersecting at center point 33. It is
to be understood that additional configurations are possible, e.g.,
triangular or circular. FIG. 12 is a side view of the FIG. 7
embodiment along cut line A. Two intersecting center lines 35 are
depicted as dashed lines. FIG. 13 is a perspective view of the FIG.
7 embodiment. The lower reflectors 34 are depicted as dashed
lines.
[0050] FIG. 8 is a side view of another embodiment of the present
invention in which only a single light source 40 is used. Light
from light source 40 is reflected off variable focus reflector 32
and transmits through opening 15 to an area to be illuminated.
Variable reflector 32 is adjustable by adjustment device 38 over a
range of positions including those illustrated by dot-dashed line
48 and dashed line 46.
[0051] The physical size of the VFILF 30 can be as small as one
foot square or as large as twenty to thirty feet square for large
indoor or outdoor installations.
[0052] The variable focus fixture 30 can be used indoors or
outdoors. The design is the same with respect to light source or
lamp placement, aperture, and reflector design. Through the use of
multiple lamps and the use of the variable output single constant
source light fixture, such as the one described in co-pending
application entitled, "Variable output single constant source light
fixture" filed on Dec. 1, 2000 having application Ser. No.
09/726,394 and by the same inventor hereby incorporated by
reference in its entirety into the present specification, it is
possible to have a totally dimmable, focusable indirect lighting
fixture. The variable output single constant source light fixture
and the VFILF are computer controllable and intended to be used
together; either through a single combined interface or through
separate individual interfaces.
[0053] The practicality of the VFILF 30 is easy to demonstrate, as
depicted in FIG. 14. In the typical conference room 54, there is a
need for variable intensity general illumination for normal
meetings, note taking, and conversations. This ambient lighting
should have a beam angle of 150 degrees so that there is light
everywhere and the minimum to maximum ratios of illumination in the
room is a very low level. This ambient lighting can be accomplished
by using a VFILF 30A adjusted similar to the fixture 30 of FIG. 4.
The intensity may need to be adjusted because of slide
presentations, computer projected images, or video presentations,
e.g., presentations at whiteboard 58. If a conference table 56 is
in use and people are seated at the table reading, working, or
looking at documents then a higher level of illumination is
required on the conference table than elsewhere in the room. Here,
fixture 30A adjusted similar to the fixture 30 of FIG. 5 is used to
illuminate only the conference table with high quality indirect
lighting.
[0054] The use of whiteboards 58, chalk boards, or wall displays 60
may require a higher degree of illumination on a particular wall.
Asymmetrical focusable indirect lighting fixtures 30B and 30C,
e.g., the fixtures depicted in FIGS. 8 and 10, can be used to
accomplish this task. Alternatively, a single fixture having
separately adjustable left and right-hand reflectors 32, e.g., the
fixture 30 of FIG. 11, may be used in place of fixtures 30B and
30C.
[0055] It is advantageous that a given fixture can be offered in
different distribution angles or beam spreads. If a customer knows
the mounting height of the fixture and the size of the room or the
size of the task area to be lit, and the desired intensity of the
illumination of the room or area, the fixture can be set to use the
least amount of fixtures to accomplish these objectives. Some
direct illumination fixtures are able to do this now, but not with
recessed or surface mounted down lighting fixtures.
[0056] The outdoor applications of the VFILF can be for parking lot
lighting outdoors where even illumination and minimum glare are
required or any other outdoor area lighting application. The indoor
applications are unlimited but the primary use is for large open
office areas where computer monitors are being used is an urgently
needed application. Screen glare from direct lighting fixtures is a
recognized cause of Computer Vision Syndrome (CVS) and the VFILF
will eliminate the glare.
[0057] Reducing the connect load for lighting measured in watts per
square foot, while providing even illumination without glare is one
of the benefits of VFILF. The presence of vertical foot-candles
from indirect lighting is extremely important to good illumination
since what we see most is vertical surfaces. We rarely look
directly down on a horizontal surface to read or study
something.
[0058] Current lighting practices only measure horizontal
foot-candles as a measure of the illumination on a work surface. If
the light is coming from a direct light fixture it is coming
straight down and little is being sent sideways to provide vertical
illumination measured by vertical foot-candles. Television lighting
directors were among the first to recognize the importance of
vertical foot-candles and to measure them. Football fields,
basketball floors, and hockey arenas also had to have the proper
horizontal lighting measured in vertical foot-candles so events
could be televised.
[0059] Vertical foot-candles measure the light that is being
directed in a horizontal direction. By having horizontal light from
two directions converge on an object it is easier to see the depth
of field or spherical shape of an object.
[0060] It will be readily seen by one of ordinary skill in the art
that the present invention fulfills all of the objects set forth
above. After reading the foregoing specification, one of ordinary
skill will be able to affect various changes, substitutions of
equivalents and various other aspects of the invention as broadly
disclosed herein. It is therefore intended that the protection
granted hereon be limited only by the definition contained in the
appended claims and equivalents thereof.
[0061] For example, even though a pair of light sources is
described in combination with a second variable focus reflector
having two concave surfaces, it is to be understood that multiple
light sources may be arranged to provide luminance to each of the
concave surfaces. In other words, there does not have to be a one
to one correspondence of light sources to concave or curved
surfaces on the second reflector.
[0062] Further, two or more curved reflective surface panels may be
used in place of the single curved reflective surface described in
relation to the variable focus reflector 32. Individual concave or
curved panels would be joined at center point or center line 33 as
necessary to reflect light from light source 40 toward an area to
be illuminated.
[0063] Further still, it is to be understood that upper reflector
32 may be a different curve or shape depending on the intended use.
For example, the upper reflector 32 may have an annular,
elliptical, or parabolic cross section.
* * * * *